The present invention relates to a method for determining a machining method in the numerical control information generating function which forms information for numerical control prior to machining, and more particularly to a method for determining the type and scope, i.e.-inherent limitations, of the machining in each step in an inner diameter machining.
There has been realized a numerical control information generating function which, when necessary data are inputted using a graphic display screen of the interactive type, forms the numerical control information such as NC programs from design drawings. This function permits inputting of the shape to be machined simply by pressing suitable keys on the panel according to the shape of component part on the design drawings. In the numerical control information generating function as above described, information necessary for setting data is conveniently displayed in graphics, and various data such as dimensions may be inputted in response to questions asked in easy and everyday language which laymen can understand. Furthermore, as soon as all the data necessary for forming numerical control information are inputted, the shape of a blank or the shape of a machining is instantly displayed, automatic calculation of numerical control data is started, tool tracks are graphically displayed and the numerical control information is formed.
The function of the numerical control information generating function generally comprises the following steps 1 to 10:
1. Selecting a work material PA1 2. Selecting a graphical type PA1 3. Inputting the shape and dimension of a work PA1 4. Inputting the shape and dimension to be machined PA1 5. Inputting the original point of the machine and the turret position PA1 6. Selecting the types of machining PA1 7. Selecting tools PA1 8. Determining the scope, i.e.-inherent limitations, of each type of the machining PA1 9. Inputting the cutting conditions PA1 10. Calculating the tool paths PA1 center counterboring PA1 drilling PA1 rough machining of inner diameter PA1 end face rough machining PA1 rough machining of inner diameter PA1 center counterboring PA1 drilling PA1 end milling PA1 rough machining of inner diameter PA1 end milling PA1 rough machining of inner diameter
Necessary data are sequentially inputted to eventually form the numerical control information.
In the conventional function described as above, after the steps of inputting the blank shape and the machining shape, an operator determines which area of the blank should be machined in each step and what tool should be moved in which direction, and determines the order of use of the tools, and inputs the necessary data according to the order thus decided. Although the conventional method is flexible as the operator can freely select the order and scope of use of the tools, the operator requires certain skills and experience with regard to machining and therefore, a beginner operator sometimes finds the step of setting various data difficult and cumbersome.
The conventional method requires a great deal of time in inputting the data since it requires selecting the types of machining, determining their order, and inputting each type of tool, cutting direction, machining scope, i.e.-inherent limitations, and cutting conditions for each type of machining. In order to overcome such short comings, Japanese Laid-Open Patent Application No. 126710/1985 teaches a method which stores in advance the order of the machining steps, evaluates for each step which machining types are necessary in the above order, and automatically determines, if necessary, the scope and cutting direction for each given machining operation. However, it teaches only one way of determining which types of machining and their scope are necessary. Particularly, in the case of inner diameter machining, where various machining steps are needed depending on the shapes and size of each of type of machining and the blanks, it becomes impossible to select an optimal type and scope of machining. For example, when the machinings are to be roughly machined from the blanks as shown in FIGS. 1A, 1B and 1C, the types of the machining to be selected by the conventional method are determined indiscriminately:
and the machining scopes are determined as shown in FIGS. 2A, 2B and 2C.
However, when an operator actually designates the types and scope of the machining, the types of the machining for the case FIG. 2A will be:
and the scope of the machining becomes set as shown in FIG. 3A. In the case of FIG. 3B, the types of the machining are generally set:
while the machining scope is set as shown in FIG. 3B. Moreover, in the case of FIG. 3C, the types of the machining are:
and the scope is set as shown in FIG. 3C.
As illustrated as above, the conventional method could not quite correspond optimally to the various needs in the machining steps as the types and scope of the machining are determined without considering the shape and dimension of the machinings and the blanks.
Although the conventional automatic programming systems automatically determine the type and scope of the machining for machining a part simply by inputting the shapes of the machining and the blank, none of them can determine the types of machining after evaluating the shapes and size of the areas to be machined that are defined by the shape of the machining and the blank. They could only determine unilaterally the type and scope of the machining for inner diameter machining (especially small diameters) which requires various machining methods depending on the shapes and size of the machining area.